Non-unitary limits on different textures for low-scale seesaw models

TL;DR

This paper investigates the limits on non-unitary effects in low-scale seesaw models with heavy neutral leptons, analyzing how flavor symmetries influence observable deviations in neutrino experiments and lepton flavor violation.

Contribution

It provides a detailed analysis of non-unitary effects in linear and inverse low-scale seesaw models, highlighting the impact of flavor symmetries and specific lepton flavor violation scenarios.

Findings

Non-unitary effects can be constrained by neutrino oscillation data.

Flavor symmetries restrict the parameter space of seesaw models.

Observable deviations depend on the presence or absence of lepton flavor violation.

Abstract

New heavy neutral leptons lead to non-unitary effects in models for neutrino masses. Such effects could represent a sign of new physics beyond the Standard Model, leading to observable deviations in neutrino oscillation experiments, lepton flavor violation, and other precision measurements. This work explores the parameter space of the linear and inverse low-scale seesaw models based on flavor symmetries consistent with neutrino oscillation experiments. In particular, we investigated the violation of unitarity when the lepton flavor violation is absent and when only one lepton flavor-violating channel is present.